Fuel systems



June 4, 1968 R. J. POWELL ETAL FUEL SYSTEMS 3 Sheets-Sheet l OriginalFiled April 11, 1966 INVENTORS. JAMES E. CHAMPION ROBERT J. POWELL,DECEASED BY RUTH B. POWELL, ADMINISTRATRIX M, um, W

ATTORNEY June 4, 1968 R. J. POWELL ETAL 3,336,427

FUEL SYSTEMS Original Filed April 11, 1966 l sheets'sheet 2 as 04 llA3.5

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' mvzmons JAMES ECHAMPION RCBERT J POWELL. DECEASED BY RUTH B. POWELL,ADMINISTRATRIX nrrmwrn 7 June 4, 1968 R. J. POWELL ETAL 3,386,427

FUEL SYSTEMS 3 Sheets-Sheet 3 Original Filed April 11, 1966 Fee. 5

m .NS X m 0 G T TMMA mm m WCM6 IEWM Q N D E wh m Jmm w wmM R B m m m m A'TORIVYS United States Patent 3,386,427 FUEL SYSTEMS Robert J. Powell,deceased, late of Muskegon, Mich., by Ruth B. Powell, administratrix,Muskegon, Mich, and James E. Champion, Muskegon, Micln, assignors toContinental Motors Corporation, Muskegon, Mich., a corporation ofVirginia Original application Apr. 11, 1966, Ser. No. 541,650, nowPatent No. 3,365,878, dated Jan. 30, 1968. Divided and this applicationMar. 31, 1967, Ser. No. 627,562

Claims. (Cl. 123-119) ABSTRACT OF THE DISCLOSURE A system for meteringthe fuel delivered to a turbocharged engine including an engine drivenfuel pump, a controller for regulating the pressure of the fuel and forbypassing fuel and which functions in accordance with superchargerpressure upstream of the throttle, a control for varying fuel deliveryfrom the controller relative to throttle position, a manual control forselectively varying fuel delivery from the throttle control to providefor economy cruise and idle cut-off and a device for controllingturbocharger speed which is responsive to discharge pressure of thethrottle with an atmospheric pressure controlled override at the abovecritical altitude.

This application is a division of our copending application Ser. No.541,650, filed Apr. 11, 1966, now Patent No. 3,365,878, dated Jan. 30,1968, which in turn was a division of our application Ser. No. 427,210,filed J an. 15, 1965, now abandoned, which in turn was a continuation ofSer. No. 320,389, filed Oct. 31, 1963, now abandoned.

The present invention relates to fuel systems for internal combustionengines and more particularly to a continuous flow fuel-air chargingsystem preferably adapted for utilization in turbocharged multi-cylinderengines for aircraft and integrating the operation of the turbochargercontrol with an improved manifold pressure controller and an automaticcompensating fuel controller to produce optimum function of enginesunder all conditions.

Under standard ambient conditions from seal level to critical altitude,the horsepower output from a multi-cylinder turbocharged aircraft engineremains almost constant with a constant manifold pressure. Manifoldpressure, since it depends at least in part upon supercharger airflow,can be regulated to maintain the desired constant pressure at anyselected position of the throttle by providing a controller whichregulates the speed of the turbine at all throttle positions in responseto variations in supercharger discharge pressure upstream of thethrottle and the throttle position. Ideally, for all altitudes up tocritical, at any selected throttle setting, absolute manifold pressurewill be automatically maintained at a constant in the present invention,so that the pilot will not be required to continually adjust thethrottle. At the above critical altitude, an automatic control isprovided to modify or override the manifold pressure controller,retaining a selected maximum ratio of manifold pressure to altitudepressure to prevent turbocharger overspeeding and overheating. Further,turbocharger discharge pressure is used for air aspirating fuelinjection nozzles and to automatically adjust fuel pressure tocompensate the fuel flow to the cyl- 3,386,427 Patented June 4, 1968inders during acceleration when the turbocharger boost produced by themanifold pressure controller has not caught up with the positioning ofthe air throttle, and at critical altitude and above where the airthrottle is positioned to be fully opened to maintain the desired ratioof manifold pressure to atmospheric pressure.

An important function of the present fuel pump control is to adjust fuelpump outlet pressure and hence fuel flow at altitude when theturbocharger is not working. On all naturally aspirated engines withoutan automatic mixture control on the fuel metering system, it isnecessary to manually lean at altitude. On a turbocharged engine, aslong as the turbocharger is working, leaning is not required except foreconomy cruise. However, when the power is reduced to a low level, asfor rapid descent, supercharger outlet pressure drops to approximatelyambient pressure, and leaning is required if the engine is to continueto function. The present fuel pump control accomplishes this leaningautomatically. The device is also important in improving accelerationand throttle response in progressing from natural aspiration of theengine to supercharging.

Thus, an object of the present invention is to improve engineperformance by producing a pneumatically controlled fuel-air chargingsystem designed for Optimum engine operation.

Another object of the invention is to improve engine fuel-air controlreliability by providing a control system readily operated with littleeffort.

A further object of the invention is to improve engine operation byproviding a fuel-air charging system controllable with maximum safety tothe engine and supercharger.

Yet another object of the invention is to prevent overloading,overspeeding and overheating of an engine and its turbocharger byproviding an improved fuel-air charging control system.

Still another object of the invention is to improve engine operationunder all conditions by providing an improved and simplified controlsystem functioning fast enough to prevent manifold pressure or speedsurging during operation.

Yet a further object of the invention is to improve automaticturbocharged engine fuel pump controls by providing a bypass meteringmeans automatically varying fuel pump outlet pressure and hence fuelflow to satisfy engine requirements at all times.

It is another object of the present invention to increase economies inturbocharged internal combustion engines by providing a control systemfor automatically regulating supercharger air flow to maintain a desiredconstant manifold pressure for each position of the air throttle for allaltitudes up to critical.

It is still another object of the present invention to simplify thecontrols of internal combustion engines having a turbocharger byproviding an automatically operating supercharger airflow regulatingsystem.

Still further objects and advantages of the present invention willreadily occur to one skilled in the art to which the invention pertainsupon reference to the following drawings illustrating a preferredembodiment of the invention and in which like reference characters referto like parts throughout the several views and in which:

FIG. 1 is a diagrammatic representation of a preferred systemincorporating the present invention.

FIG. 2 is a cross-sectional diagrammatic view of a preferred fuel pumpassembly, bypass metering device and vapor separator of the presentinvention.

FIG. 3 is a cross-sectional diagrammatic view of a preferred manifoldpressure controller of the present invention.

FIG. 4 is a cross-sectional view of a preferred fuel distributingmanifold and mixture control valve assembly of the present invention,and

FIG. 5 is a cross-sectional view of a preferred pressure controlledwaste gate actuator device of the present invention.

Referring to the drawings for a more detailed understanding of theinvention, FIG. 1 illustrates diagrammatically the major components ofthe present fuel-air charging control system of the present invention,the system comprising a supercharger driven by an exhaust turbine 11,the combination normally referred to as a turbocharger. The superchargerdelivers compessed air through a duct 12 to the intake of the cylinders13 (only one shown) of an internal combustion engine. Exhaust gasesselectively drive the turbine 11 depending on the position of aWaste-gate valve 14 in an exhaust bypass duct.

An air throttle valve 15 is manually operable through a throttle lever16 and is connected through throttle linkage 17 (dash line) to amanifold pressure and fuel metering controller assembly 18.

Fuel is delivered to the controller assembly 18 through a conduit 19 bya fuel pump assembly 20, taking fuel from the fuel tank 21, whichcontains an electrical auxiliary fuel pump 22, the fuel passing througha filter 23. Vapor is removed from the fuel and returned to the tank 21through a conduit 24 containing a check valve 25.

The controller assembly 18 operates a waste gate actuator as will behereafter explained, the actuator correspondingly operating to vary theposition of the waste gate valve 14. When the valve 14 is closed,exhaust gases in a duct 29, which are under pressure, are directed tothe turbine 11 which is drivingly connected with the supercharger 10 asindicated by the dash line 31. Ex pended exhaust gases are thendischarged through an exhaust pipe 32.

When the valve 14 is open, exhaust gas pressure is bypassed through aduct 33, and the turbine power is correspondingly reduced. Varyingpositions of the valve 14- produce correspondingly varying bypass ofexhaust gases around the turbine 11 so that degrees of turbochargeroperation from no power to full power are obtainable.

The controller assembly 18 includes a fuel metering control subassembly18A which variably directs fuel through a conduit 34 to a combinationfuel manifold and mixture control valve 35, which in turn delivers fuelthrough conduits 36 to vented fuel injection nozzles 37 mounted toinject fuel into the air intake manifold adjacent the cylinder airintake valves 38 (only one shown).

The present system operates to maintain optimum fuel-air ratios andmanifold pressures by providing desired fuel delivery pressures andflow, and by variably operating the supercharger. Function of the systemcomponents is as follows:

Fuel pump, relief valve and fuel pressure controller assembly 20, FIG. 2

This preferred assembly 20 comprises a housing 40 having an intakechamber 41 into which fuel from an inlet conduit 42 is angularlydirected to produce a centrifugal swirl, in which vapors will becentralized. Fuel is normally drawn out of the chamber 41 through apassage 43, pressurized by means such as a gear pump 44, and deliveredvia discharge passage 45 to the conduit 19. The pump 44 is adapted byany means such as a splined shaft 46 to be driven by the engine (notshown).

A passage 47 provided in the housing 40 directs some pressurized fuelthrough a fuel jet orifice 48, which fuel crosses an opening 49,positioned at the top center of the chamber 41, into a passage 50connected to the vapor return conduit 24. The effect of the fuel jet 48is to produce suction for positive removal of vapor from the chamber 41.This vapor sepraator is substantially like that shown in our prior U.S.Patent No. 2,901,031.

A bypass check valve 51 is provided between the chamber 41 and thepassage 45 and operates to open for bypassing fuel from the auxiliarypump 22 (FIG. 1) to the system during engine starting or for emergencyoperation in the event of failure of pump 44.

A relief valve assembly 20A operates as a downstream pressure control tovary delivery rate of the pump. It is mounted on the housing 40 andcomprises a two-part housing 55 having an inlet chamber 56 connected bya passage 57 with the pump discharge passage 45, and an outlet chamber58 connected by a passage 59 with the pump intake chamber 41.

Intermediate the chambers 56 and 58 is a valve member 60 carried by adiaphragm 61 forming one wall of the outlet chamber 58. The other sideof the diaphragm is exposed to a chamber 62 openingly connected by apassage 63 with the interior of an aneroid housing 64 which in turn isopenly connected with a conduit 65 leading from the superchargerdischarge pressure end of the duct 12 (FIG. 1) upstream of the throttlevalve 15.

The valve 60 is biased toward a closed position by a spring 66 whosecompression may be manually adjusted by any means such as a screw 67. Innormal operation, the valve 60 will be open to a degree at all times,automatically adjusting as downstream fuel pressures tend to vary.

A variable orifice valve 68 operates to vary the delivery capacity ofthe pump. It is disposed intermediate the passage 57 and chamber 56 andis carried on a shaft 6? connected to an aneroid or bellows 70 disposedin a pressure chamber 71 of the housing 64 and mounted thereon by meansof a manually adjustable screw 72 for calibration adjustment.

The variable orifice valve 68, as controlled by the aneroid 70, acts asan automatic fuel pump control. Its most important function is to adjustfuel pump discharge pressure, and hence fuel flow, at altitudes wherethe turbocharger is not working. On naturally aspirated engines havingno automatic mixture control in the fuel metering system, it isnecessary to manually lean at altitude. On a turbocharged engine such asthe present, as long as the turbocharger is working, leaning is notrequired except for economy cruise. However, when the power is reducedto a low level, as in rapid descent, supercharger outlet pressure dropsto approximate ambient air pressure, and leaning is required if theengine is to continue to function. In the present device, this isaccomplished as follows:

When supercharger discharge pressure drops, the pressure in chamber 62(which is openly connected through passage 63, chamber 71 and passage 65to air duct 12), decreases to permit the valve 60 to open wider, andsimultaneously the aneroid 70 expands, opening the orifice valve 68,thereby reducing fuel pump discharge pressure by relieving more pressurethrough the relief valve, thus automatically leaning the fuel-airmixture of the engine.

The relief valve 60 regulates fuel pressure at all times, permitsadjustment of idle r.p.m. fuel pressure and compensates for lack of fuelpump efficiency at low r.p.m., by tending to impose a substantiallyconstant maximum fuel delivery pressure on the system at any selectedmanifold pressure. Further, this type of vented diaphragm valve permitsoperation of the auxiliary fuel pump at pressures up to the setting ofthe relief valve without upsetting system calibration. The diaphragm 61must be vented to air throttle inlet pressure; i.e., superchargerdischarge pressure, or leaning out would occur at altitude. In the caseof naturally aspirated engines, the diaphragm is vented to atmosphericpressure, as described in our U.S. Patent No. 2,991,055.

As described in said patent, the fuel injection system fuel pump for anaturally aspirated engine has a fixed orifice in series with the reliefvalve. In the present turbocharged engine, the fixed orifice is replacedby the previously described variable orifice valve 68 controlled by theaneroid 70 sensing air throttle inlet pressure, i.e., superchargerdischarge pressure. When this pressure rises, the aneroid 70 collapses,decreasing orifice area, and pump outlet pressure increases. Conversely,when air throttle inlet pressure drops as at altitude at low power, theaneroid expands, increasing orifice area, and pump outlet pressuredecreases. Thus the orifice is made to serve a multiple function.

Fuel metering control subassembly 18A of controller assembly 18, FIG. 3

The preferred controller assembly comprises a threepart housing, theparts designated by reference characters 75, 76 and 77.

Fuel under regulated pressure is delivered from the fuel pump assemblyvia conduit 19 to an inlet chamber 78 in the housing 77. A fuel controlshaft 78A is rotatably carried by and extends through the left handportion 76A of the housing 76 and has secured to the inner end a spoolelement 79 provided with a slot 80 in one side open to an annular groove81. The spool element 79 is disposed in an outlet chamber 82 in thehousing 77, the outlet chamber being openly connected with the fueldelivery conduit 34.

A partition element 83 separates the inlet chamber 78 from the outletchamber 82 and is biased by a spring 84 into sealing engagement on thespool element 79. The partition element 83 has a port 85 which is invariable registry with the slot 80 in the spool element 79.

The outer end of the shaft 78A is provided with a lever 86 which, asseen in FIG. 1, is slaved to the air throttle valve 15 from a lever 87connected thereto.

As the throttle control lever 16 is manually moved to open and close theair throttle valve 15, the shaft 78A is rotated to correspondingly openand close the area of registry between the slot 80 in spool 79 and theport 85 in element 83, thus metering fuel flow to the conduit 34.

Fuel distributing manifold-mixture control valve assembly 35, FIG. 4

The assembly 35 comprises a two-part housing 90-91. The housing 90 has abore 92 openly connected at one end to the fuel conduit 34 andcontaining a rotatable shaft 93. The inner end of the shaft 93 has agroove 94 Which variably registers with a port 95 openly connecting thebore 92 with a chamber 96 provided in the housin 91.

The housing 91 has a stepped distributing chamber bore 97 in which iscarried a sliding plunger 98 having an inner recess 99 connected byports 100 with the chamber 96, a fuel strainer screen 101 being disposedin the chamber 96 as shown. A spring biased check valve 102 is disposedbetween the recess 99 and the ports 100.

The upper end of the plunger 98 has a groove 103 engaged with a slot 104provided in the shaft 93. The outer end of the shaft 93 has securedthereto a manually operable lever 105. This is the mixture control andidle cut-off lever. The chamber 96 below an annular seal 96A isconnected by a conduit 106 to a metered fuel pressure gage 107 (FIG. 1)installed, for example, on the aircraft control panel. A plurality ofdistributing ports 108 eonnect the chamber 97 with the conduits 36delivering fuel to the vented fuel injection nozzles 37.

Each of the nozzles 37 has a fixed fuel jet restriction 109 injectingfuel across an air space 110 into a fuel discharge passage 110 openinginto the air intake manifold 12 adjacent the cylinder intake. The airspace 111 is connected with supercharger, discharge pressure by means ofa conduit 112, so that the nozzles are always sensing air throttle inletpressure to act as a downstream pressure control uniformly withoperation of the relief valve 20A. Air aspiration assists fuelatomization in the nozzles 37 before the fuel enters the manifold 12,and prevents siphoning of fuel from the fuel lines 36 on idle cut-offwhen manifold suction increases.

In the standard fuel injection system on naturally aspirated engines,vented nozzles such as are described in our prior Patents Nos. 2,913,233and 2,983,491, sense ambient pressure as do the fuel pressure gage, fuelpump and air throttle. On a supercharged engine, there is a new pressureat the air throttle inlet which is above ambient, and hence all thosecomponents which are involved n fuel metering must now sensesupercharger discharge pressure rather than ambient, to obtain a fuelcoordination of all units.

In operation, the fuel control lever 86 (FIG. 3), being slaved with theair throttle 15 (FIG. 1) through lever 87 and linkage 17, operates uponmovement of the throttle lever 16 to rotate the shaft 78A (FIG. 3) andthe spool 79 secured thereto, opening and closing the orificesimultaneously respectively with opening and closing of the air throttle15, thereby metering fuel delivery to conduit 34.

Metered fuel under regulated pressure is thus delivered to the manifoldvalve of FIG. 4, entering passage of chamber 96, through ports to thecenter, op ning the check valve 102, passing into chamber 99 in thevalve plunger 98, thence passing into manifold chamber 97 for deliverythrough ports 108 to conduits 16.

Fuel-air mixture is selectively manually adjusted from the lever 105.Rotation of the shaft 93 variably controls the area of orifice 95 opento the slot 94, so that the mixture may be leaned for economy cruise.The shaft rotates through an angle of about 75, and final travel of thelever and shaft 93 forces the plunger valve 98 down, closing off ports190 from the chamber 96 and also closing 01f all delivery ports 108 fromthe chamber 97 and from each other, thus producing a positive idlecut-off of the engine. A somewhat similar valve is illustrated in ourprior Patent No. 2,913,231, but in the present case, the mixture controlfunction is combined with the manifold shut-off for simplicity andreliability of operation and more economical manufacture.

The degree by which the series-connected orifice 80 (FIG. 3) and passage95 (FIG. 4) are opened determine the amount of fuel delivered to theengine, orifice 80 being controlled by the throttle in changing enginespeed, and passage 95 being controlled by a mixture control lever tovary fuel-air ratio as desired.

Controller assembly 18, FIG. 3, and waste gate actuator 30, FIG. 5

Housing port 76 of the assembly 18 (FIG. 3) is provided with an aneroidchamber as shown, openly connected through a conduit 121 (FIG. 1) andport 122 with the air delivery conduit 12 upstream of the throttle valve15.

An aneroid 123 in the chamber 120 is carried on a plunger 124 whichextends through a bore 125 and is provided with a cam follower 126riding in a cam slot 127 provided in the throttle-slaved shaft 78. Thefollower 126 is urged into engagement with the cam slot 127 by a spring128.

The other end of the aneroid 123 carries a hollow shaft 129 slidable ina bore 132 in the housing portion 75 and having an open end to the rightas shown variably adjusted toward and away from the end of a plug 130adjustably threaded into the housing portion 75. The end of the shaft129 adjacent the aneroid 123 has ports 131 open at all times to thechamber 120.

A second aneroid 135 is mounted in the chamber 120 on a manuallyadjustable screw 136 and is connected at the other end to a diaphragmassembly 137 carrying a shaft 138 slidable in a bore 139 provided in thehousing portion 75. A passage 147 connects the aneroid chamber 120 wit-hthe chamber 146. The poppet valve 145 is, as shown, spring loaded to theclosed position. The diaphragm 137 separates the chamber 120 from anatmospheric pressure chamber 141 provided in the housing portion 75 andvented to atmosphere through a port 142. A bore 144 extends transverselyacross the housing portion 75 and is vented to atmosphere at one endthrough a restricted orifice 142A.

A conduit 159 connects the bore 144 with one side of the interior of thepreferred waste gate actuator housing 151 shown in FIG. 5. The otherside of the housing 151 has a vent 152 to atmosphere. The interior ofthe housing 151 is divided by a diaphragm assembly 153, which, hav ing acentral piston 154 as shown, is axially slidably mounted on a pin 155,secured to one side of the housing 151. The diaphragm 153 defines acontrol chamber 156 and a vent chamber 157, and is urged to decreasecontrol chamber volume by any means such as a spring 158. The piston 154extends through the housing 151 and is connected by linkage 159 with thewaste gate 14.

Operation of the controller 18 to vary the position of waste gate 14through the actuator 30 is as follows:

Rotation of the shaft 78 on movement of the air throttle 15 andconnecting linkage 17 varies the axial position of or compression on theaneroid 123 by moving of the cam follower 126 on the cam 127. For eachposition of the air throttle 15 there is a corresponding meteringposition in the fuel control positon of the controller as describedpreviously and also a corresponding position of or compression on theaneroid 123 and its associated hollow shaft 12? relative to the setposition of the plug 130.

Supercharger discharge pressure from the conduit 121 (FIG. 1) enters theinlet 122 and the aneroid chamber 120, and this pressure is sensed byboth aneroids 123 and 135 and by the diaphragm 137. Vlith the engineoperating and supercharger pressure entering chamber 120, the aneroid123 will be partially collapsed, moving the open end of the shaft 129off its seat on the plug 130, so that pressure from the chamber 120normally escapes through the hollow shaft 129 into the bore 144. Thispressure is more than can be vented through the orifice 142A so it istransmitted through conduit 150 to the waste gate actuator 156, movingthe diaphragm 153 and piston 154 to position the waste gate 14 to itsdesired setting. The Waste gate 14 position determines the proportion ofexhaust pressure directed through the turbine 11, thereby controllingthe degree of supercharging of the engine to establish the desiredmanifold pressure for each air throttle position.

When pressure in the controller chamber 120 tends to go below thesetting called for by the cam 127, the aneroid 123 expands, moving theopen end of the hollow shaft 129 towards its seat on the inner end ofthe plug 130, cutting off supercharger pressure to the bore 144, conduit1411, and actuator chamber 156. The actuator spring 158 moves thediaphragm 153 and piston 154 to the right, actuating the waste gatetowards its closed position and thus increasing supercharger pressure byincreasing turbocharger speed. Air from the chamber 156 flows backwardthrough conduit 150 into the bore 144 of the housing portion 75 (FIG. 3)and is vented therefrom to atmosphere through the port 142A.

Conversely, when pressure in the chamber 120 tends to go higher than therequired setting, the aneroid 123 tends to collapse, unseating the openend of the shaft 129 from the plug. More supercharger discharge air willflow through the shaft 129 into the bore 144, thus raising the pressurein the actuator chamber 156, moving the diaphragm 153 and piston 154 tothe left, and actuating the waste gate 14 towards its open position.This decreases supercharger pressure by decreasing turbocharger speed.

Thus, this part of the controller achieves a balance for every airthrottle position, in which just the right amount of superchargerdischarge pressure is admitted to the actuator chamber 156 to maintain astability of or constant straight-line discharge pressure and hencemaintain air intake manifold absolute pressure at all altitudes.

The upper portion of the controller, that portion including the aneroid135 and associated parts and chamhers, is called the pressure ratiosection. Its function is to override the above mentioned controlleroperation when the aircraft reaches critical altitude, to preventoverspeeding and over-temperature operation of the turbocharger. Foreach absolute pressure value, a critical altitude limit is established,above which the absolute pressure must decrease to prevent overspeeding.The diaphragm and aneroid of the pressure ratio section as presentlyarranged are preferably constructed and set so that the poppet valvewill operate at about a 22:1 ratio.

For example, at 36 absolute pressure, critical altitude will be about16000, since 16000 equals In operation, when atmospheric pressure inchamber 141 to the right of the diaphragm 137 decreases, so that theratio of pressures between chambers and 141 reaches about 2. 2:1, theshaft 138 will be moved to the right, opening the poppet valve 145.Pressure from chamher 120 enters the bore 144 via passage 147 andchamber 146, thus increasing the pressure transmitted to the waste gateactuator 30 to open the waste gate 14 and decrease turbocharger speed.This device operates to produce a sharp break in the pressure curve atcritical altitude.

Thus a system is provided in which an optimum relationship is maintainedbetween manifold pressure and throttle position in a turbosuperchargedengine at all altitudes up to critical, at which point the pressureratio section overrides the basic control means to prevent superchargeroverspeed.

It will be noted that the waste gate actuator 30 may be operated by apressure admitted from any source, (which pressure admission iscontrolled by the aneroids 123 and 135. The present system preferablyuses supercharger discharge pressure for this function to provide afully pneumatically operating system having very simplified and reliablecomponents.

In summary, the present invention consists of a fuel-air charging systemin which fuel metering is based upon three parameters; namely,supercharger discharge pressure upstream of the throttle valve, throttleposition, and engine speed, and in which turbocharger speed isdischarge-pressure controlled relative to selected settings of thethrottle, with an atmospheric pressure controlled override at and abovecritical altitude.

The system of metering the fuel delivered by the engine driven pump(variable with engine speed) comprises, in series, the followingcomponents:

1) Bypass metering of the charging fuel including (a) variable orificevarying delivery capacity as a function of supercharger pressureupstream of the throttle; and .(b) a downstream pressure control reliefvalve varying delivery rate as a function of supercharger pressureupstream of the throttle;

(2) A throttle control varying fuel delivery from the bypass meteringdevice relative to throttle position;

(3) A manual mixture control selectively varying fuel delivery from thethrottle control for economy cruise and idle cutoff; and

(4) A fixed restriction at the injection nozzle with downstream pressurecontrol, which is uniform with and compensates for the operation of therelief valve.

[Both the relief valve and the fixed orifice injection nozzle providepressure control on the fuel relative to controlled superchargerdischarge pressure.

Although we have described only one embodiment of 16.21 Hg abs. andequals (approx) 9 the invention, it will be apparent to one skilled inthe art to which the invention pertains that various changes andmodifications may be made therein without departing from the spirit ofthe invention or the scope of the appended claims.

We claim:

1. A fuel-air charging system for an internal combustion engine havingengine cylinders, an air intake means directing air to said cylindersand provided with a throttle valve, an exhaust-driven turbochargerincluding a turbine and a supercharger driven thereby for pressurizingair upstream of said throttle valve, a fuel injection nozzle forinjecting fuel into said air intake means downstream of said throttlevalve, an engine driven fuel pump having an inlet and an outlet andvarying fuel pressure with engine speed, and means conducting fuel fromthe pump outlet to the injection nozzle, said system comprising:

(a) bypass metering means connected in parallel with the pump andoperable in response to variations in supercharger discharge pressureupstream of said throttle valve to vary the rate and capacity of fueldelivered by said pump by bypassing fuel variably from the pump outletto the pump inlet,

(b) fuel flow metering means connected with the pump outlet to receivefuel as controlled by said bypass metering means, and operably connectedwith said throttle valve to vary flow of fuel to said injection nozzle,

(c) said injection nozzle having a fixed orifice in series with theaforesaid fuel flow metering means, and means downstream of said orificecontrolling fuel pressure thereat responsively with variations insupercharger discharge pressure upstream of said throttle valve, and

(d) said turbocharger having control means controlling superchargerdischarge pressure in response to variations in throttle position andvariations in supercharger discharge pressure upstream of said throttlevalve.

2. The fuel-air charging system as defined in claim 1 and in which saidcontrol means includes means operable at and above a selected altitudeto modify the control of supercharger discharge pressure in response tovariations in the ratio of supercharger discharge pressure upstream ofsaid throttle valve to absolute atmospheric pressure.

3. The fuel-air charging system as defined in claim 1 and in which saidbypass metering means comprises:

(a) a valve connecting the pump inlet and outlet and having meansbiasing said valve toward a closed position,

(b) means controlling valve position in response to variations in pumpdischarge pressure and supercharger discharge pressure upstream of saidthrottle valve, and

(c) a variable orifice intermediate the pump outlet and said valve andvariable in response to variations in supercharger discharge pressureupstream of said throttle valve.

4. The fuel-air charging system as defined in claim 1 and in which saidcontrol means comprises:

(a) a waste gate for said turbocharger to variably bypass exhaust aroundthe turbine,

(b) a pressure operated actuator for said waste gate,

(c) a controller delivering pressure to said actuator variablyrespectively to variations in throttle position and superchargerdischarge pressure.

5. The fuel-air charging system as defined in claim 4 and in which saidcontroller comprises:

(a) a housing having a control chamber openly connected with said airintake means upstream of said throttle valve,

(b) a pressure responsive means in said chamber and connected forvariable positioning with movement of said throttle valve, and

(c) valve means carried by said pressure responsive means and operablein response to pressure changes in said chamber to variably deliversupercharger discharge pressure from said chamber to said actuator.

6. The fuel-air charging system as defined in claim 5 and including:

(a) a second pressure responsive means in said chamber,

(b) valve means carried by said second pressure responsive means andoperable in response to pressure changes in said chamber and to changesin atmospheric pressure to modify pressure delivered to said actuator bysaid valve means operated by the first pressure-responsive means whenthe ratio of supercharger discharge pressure to atmospheric pressurerises to and above a preselected value.

7. The fuel-air charging system as defined in claim 1 and in which saidbypass metering means comprises:

(a) a housing structure having two pressure chambers openly connectedwith said air intake means intermediate the supercharger and thethrottle valve,

(b) a passage connecting the pump inlet and-pump outlet,

(c) a pair of valves in series in said passage respectively designatedan upstream orifice valve and a downstream regulator valve, and operableto variably control bypass of fuel from the pump outlet to the pumpinlet,

(d) pressure sensing means in one of said pressure chambers and operablyconnected with said orifice valve to vary the opening thereof inresponse to pressure changes in said pressure chamber, and

(e) pressure sensing means intermediate said passage downstream of theregulator valve and the other of said pressure chambers and operablyconnected with said regulator valve to vary the opening thereof inresponse to pressure changes in said passage and in said other pressurechamber.

8. The fuel-air charging system as defined in claim 4 and in which saidcontroller comprises:

(a) a housing structure having a pressure chamber openly connected withsaid air intake means upstream of said throttle valve,

(b) a shaft rotatably carried by said housing and operably connected atone end with the throttle valve for rotation therewith and at the otherend with said fuel flow metering means for operation thereof, said shaftcarrying a cam,

(c) an aneroid in said chamber and carried by a shaft operably engagingsaid cam for axial positioning of said aneroid relative to rotation ofsaid shaft,

(d) valve means carried by said aneroid and axially movable therewith inresponse to throttle movement and to pressure changes in said chamber tovariably control pressure delivered to said waste-gas actuator.

9. The fuel-air charging system as defined in claim 8 and in which saidvalve means comprises:

(a) a pressure passage in said housing adapted for connection with saidwaste gate actuator,

(b) an axially slidable tube carried at one end by said aneroid andextending into said pressure passage, said tube having a passage open atone end in said chamber and at the other end in said pressure pas-sage,

(c) means in said pressure passage positioned to vari ably open andclose the open end of the tube in said pressure passage upon movement ofthe tube produced by pressure changes in said chamber and by throttlemovement.

10. The fuel-air charging system as defined in claim 9' and including:-

(a) a second aneroid in said chamber,

(b) a second pressure chamber in said housing and open to atmosphericpressure, said second chamber 1 1 separated from the first chamber by aflexible diaphragm,

(c) said second aneroid mounted in the first chamber and carrying asecond valve means connected to said diaphragm for operation of saidvalve means by changes in pressure differentials across said diaphragmand in pressure changes in the first chamber sensed by the secondaneroid,

((1) said second valve means being operable to variably opencommunication between said first chamber and said pressure passage tothereby modify the pressure delivered to said Waste gate actuator byoperation of the first valve means.

References Cited UNITED STATES PATENTS LAURENCE M. GOODRIDGE, PrimaryExaminer.

